An expansion holder (to be also called a stent hereinafter) is generally used to hold an internal diameter of an internal cavity of a tubular organ so as to prevent a stenosed portion of, e.g., a coronary artery from being stenosed again after the stenosed portion is expanded by a blood vessel expansion catheter.
A conventional stent used for the above purpose is a net made of a stainless steel wire (Surgery, 1986, Vol. 99, No. 2, p. 199-205) or a stent made of a unidirectional shape memory alloy (Published Examined Japanese Patent Application No. 61-6655). When a blood vessel is to be held expanded by using this stainless steel stent, the stent is inserted to a predetermined position of the blood vessel through a blood vessel expansion catheter, and a balloon arranged at the distal end of the catheter is expanded to expand the stent to the same diameter of the blood vessel. When a stent made of a unidirectional shape memory alloy is used, it is inserted to a predetermined position of a blood vessel and is warmed with warm water, thereby expanding the stent.
In either case, the stent is simply wound around and held at the distal end portion of the catheter. The outer diameter of a catheter portion around which the stent is wound is larger than that of other catheter portions. As a result, when a catheter is inserted in a relatively thin blood vessel such as a coronary artery, or when the catheter mounted with this stent is inserted into a guide catheter, the sliding operation of the catheter is degraded due to the presence of the stent mounting portion, thus posing a problem. In addition, since a conventional stent inserting/removing catheter does not have any means for assuring a position of the distal end of the catheter or a positional relationship between the catheter distal end and the indwelled stent, it is difficult to operate such a conventional catheter.
It is an object of the present invention to provide a stent inserting/removing catheter which can be smoothly slid within a blood vessel and in a guide catheter, can assure a position of a distal end portion, and can improve operability.